The AREDS Research Group developed the nine-step severity scale, which combines a six-step drusen area scale with a five-step pigmentary abnormality scale. On it, the five-year risk of advanced AMD increased progressively from less than 1 percent in step one to about 50 percent in step nine. Among the 334 eyes that had at least a three-step progression on the scale between the baseline and five-year visits, almost half showed stepwise progression through intervening severity levels at intervening visits. Replicate gradings showed agreement within one step on the scale in 87 percent of eyes.
The scale provides convenient risk categories and has acceptable reproducibility, the researchers conclude. Progression along the scale may prove to be useful as a surrogate for progression to advanced AMD. In AREDS, stereo color fundus photographs were taken at baseline, at two years and annually thereafter. Photographs were graded for drusen characteristics, pigmentary abnormalities, and presence of abnormalities characteristic of neovascular AMD. Advanced AMD was defined as presence of one or more neovascular AMD abnormalities, photocoagulation for AMD, or geographic atrophy involving the center of the macula. The researchers explored associations among right eyes of 3,212 participants between severity of drusen characteristics and pigmentary abnormalities at baseline and development of advanced AMD within five years of follow-up.
(Arch Ophthalmol 2005;123:1484-1498.)
Age-Related Eye Disease Study Research Group. AREDS Report No. 17.
Artificial Tears Offer Temporary Improvement in Visual Acuity
A common preservative-free artificial tear, carboxymethylcellulose (CMC) 0.5% provides temporary but significant visual acuity improvement in symptomatic and asymptomatic dry-eye patients, according to a nonrandomized, prospective trial in New York City.
Twenty symptomatic dry-eye patients (40 eyes) and an equal number of asymptomatic dry-eye patients, all 40 years and older, were recruited. Distance VA was measured by ETDRS chart and near visual acuity was measured by the Lighthouse Near Vision chart before and 30 seconds after instillation of one drop of CMC (Refresh Plus, Allergan). Acuity was measured with and without correction. The duration of action of CMC was measured at one-minute intervals until the patient's VA returned to pretear level.
In both groups, uncorrected and corrected near and distance vision showed a statistically significant improvement after CMC (p<.05). There was no significant difference in improvement between the two groups in all categories (p>.05). The mean duration of improvement of vision was 2.93 minutes in the symptomatic group and 3.70 minutes in the asymptomatic group (p=.036).
The effect of artificial tears on VA may be of diagnostic value in detecting ocular surface abnormality in symptomatic and asymptomatic patients, the researchers report.
(AJO 2005;140:830-835.)
Nilforoushan M, MDab, Latkany R, Speaker M.